Thanks. I’ve reported it to the Marketplace team.
Rob
Some links I found from my browser history:
https://coronalabs.com/blog/2013/06/18/guest-tutorial-delta-time-in-corona/
This was being shown by Google as one of the top results for delta time in Corona but it doesn’t show up for me right now. You can still see many forum posts referencing the tutorial like these:
https://forums.coronalabs.com/topic/56542-why-enterframe-delta-time-so-difference/
https://forums.coronalabs.com/topic/60486-applying-deltatime-to-platformer/
Another dead link is titled “Tutorial Treasury: Input Devices”: https://coronalabs.com/blog/2015/08/04/tutorial-treasury-input-devices/
I don’t remember how I found it but I have no idea what’s in it at the moment. It also seems to be referenced in a forum post: https://forums.coronalabs.com/topic/63608-connect-with-midi-keyboard-to-device-please-help-me/
I was searching for the demos for the first Graphics 2.0 contest as was looking for a way to look into the fake 3D stuff. I found the video on the Corona Labs YouTube channel but the link in the description was going for a 404.
Link: https://coronalabs.com/blog/2013/12/10/graphics-2-0-demo-contest-winners
Video on YouTube: (I’m still curious on how to achieve some of those effects by the way.)
https://www.youtube.com/watch?v=ZhX-NO0qHP0
…and the last one I found was a link from 2011. I know it’s pretty old but it’s referenced from many forum posts it seems. It would be better if it redirects to a more recent post where it shows the latest approach to replace this.
https://coronalabs.com/blog/2011/09/05/a-better-approach-to-external-modules/
Yet still no response as to why Corona is selling templates for competing platforms and how this benefits Corona users in any way?
A true story…
I wanted a musical pack but the one I really liked was only half a pack on the Corona store. So I found it on the Unity store with like 3x the tracks for less money. So as you know I am an avid Corona developer so I actually installed Unity, purchased the pack and then promptly uninstalled Unity after finally downloading the assets (you cannot download unless you have unity installed).
Long story short… have a little faith in your own product Corona!
I’m more curious how selling template for competing platforms benefits Corona Labs to be honest.
If the idea is that someone who has already invested time and effort to learn a competing system, and then randomly google an asset at the corona marketplace, will fall instantly in love with corona and abandon their existing system (before or after purchasing the asset?), I simply don’t get it.
That being said, love the corona roadmap (some positiv feedback!) 
@bgmadclown, thanks for pointing these out.
We sometimes remove content and we don’t always have a place to redirect to. If you are using bookmarks or if your looking at an old page thats linking to removed content, a 404 error is appropriate. 404 doesn’t always mean “broken link”, it can also mean that content is no longer available. In many of these blog posts, that’s the case.
All of the links you’ve shared end up going to blog posts that were removed. They may have been removed for various reasons. Some tutorials moved to the Docs site, but hopefully we did setup redirects for those. I’ll have to go through each of the URLs and see if there is a new tutorial on the docs site and get a redirect created.
Now if there is an active page on our site that isn’t going to a valid place (i.e. click here to see submission guidelines) we should either update the page to not go there, or make sure there is a place to go to and fix it if we can. There isn’t much that can be done for archived forum posts, links on 3rd party sites, or bookmarks.
For the 2.5D effects, see: http://docs.coronalabs.com/guide/graphics/3D.html
Again thanks for pointing these out.
Rob
This is exactly what I was talking about. As a beginner how am I supposed to know that the link has moved to somewhere else? And to where? Why not just update those pages - most of them are your old blog posts, so you must have access. If you ask me this is the worst option that you guys have chosen.
And I can tell you I hit A LOT of them. My first week in corona I spent more time on web.archive.com (looking at the exact pages you seem to be trying to remove - and learning from them) then on your own site. I just don’t see the point. Update the pages - put a notice on the top that this is for an older version or a link to the actual new page. At least it gives people a way forward.
Another bad one is: https://coronalabs.com/blog/2014/09/09/tutorial-working-with-curved-paths/ - this teases me with some explanation and an example program, but the example program links are not valid any more…
It seems this topic has been hi-jacked and is now about broken links
Oops sorry @anaqim. You’re absolutely right, it should be it’s own topic. There was a reason I brought it up initially but the topic should get back on track…
[EDIT] Moved the links discussion to https://forums.coronalabs.com/topic/72970-corona-blog-links/
No worries mate 
Sorry for hijacking the thread!
Back to the topic, does it really increase awareness @Rob? Do you have some positive numbers at hand that this approach is worth it?
By the way, I’m mostly talking about templates for other development platforms. I’m fine with any graphics and music assets on the Marketplace.
My vote is for Corona only templates or assets that can actually be used in Corona.
I also kind of agree about mmihajlovic statements about marketing. I saw two new video tutorials on YouTube recently, but that’s about it.
Ed is doing a helluva job and has been amazing on CoronaGeek, but you have to already BE a corona dev to discover him, I guess. For beginners Jay has some great tutorials and he has a good way of explaining things. Corona should hire him for some new tuts.
Also, I would love to check more apps that were made with Corona and from you all. I know there’s Corona stories and a forum post about this, but I think a nice page Made with Corona with app icons layed out would be more helpful. Also perhaps a YouTube channel with all video previews in one place. It would all make a better way to seduce a newbie and create somewhat a more connected environment.