Apple designates a number of different Media Types (mt values):

1   Music
2   Podcasts
3   Audiobooks
4   TV Shows
5   Music Videos
6   Movies
7   iPod Games
8   Mobile Software Applications
9   Ringtones
10  iTunes U
11  E-Books
12  Desktop Apps

So, to answer your question, the "mt=8" in iTunes links simply identifies it as being of type Mobile Software Applications .

Some people noted the you can actually drop the mt part of the link and you still end up on the expected page. This is correct, but on iOS it is helpful to attach the mt tag to tell the OS to what app to switch. When you don t add the mt part and you link to an app the OS will first fire up the iTunes app. This one then figures out that the link points to an app and then switches over to the App Store app.

Therefore it is good practice to enhance the experience for the user by adding the correct mt tag to your iTunes URLs.

Parameters:

I – Identifier: The “I” parameter includes the ID of a specific item in a collection. For example a track in an album or the episode in season of a TV show.

MT – Media Type: The MT parameter indicates which type of media the hyperlink is pointing to. The types and codes you could see are listed below (however, besides 8, 11, and 12 these parameters are often not included, or necessary).

1 – Music

2 – Podcasts

3 – Audiobooks

4 – TV Shows

5 – Music Videos

6 – Movies

7 – iPod Games

8 – Mobile Software Applications / loads in the App Store on iOS

9 – Ringtones

10 – iTunes U

11 – E-Books / loads in the iBookstore on iOS

12 – Desktop Apps / loads in the Mac App Store in OS X

Note: The MT parameter is crucial when creating your links for items not in the iTunes Store. In iOS and OS X this parameter tells the operating system which specific store to open to handle the link, and if it’s not built correctly, the customer may see an error instead of the correct item. For example, you can’t open a Mac App link in the iTunes Store and if the link points to the incorrect store (or is not there), there’s an interrupted user experience and a potentially lost conversion.

LS – Load Store: This parameter, with the value of “1” (which means “true” in the coding world), tells the Preview Page to also load the item in the iTunes Store (inside the iTunes desktop application). If you don’t use either an affiliate parameter or the LS parameter, the link will only take the user to the Preview Page in their browser. This isn’t ideal because it forces the user to then go through another click to actually purchase the product, which potentially lowers your conversation rate since it’s more work for them. We recommend always using either the LS parameter or affiliate the link to alleviate this. Because Preview Pages are desktop specific (you don’t see them in iOS) this parameter doesn’t appear to be useful for links that only exist in the mobile ecosystem.

UO – Unique Origin: This parameter identifies the tool or sources used to generated the link itself (e.g. RSS Feed Generator, Search API, Enterprise Partner Feed, etc.). This helps identify where the link came from for your benefit, but doesn’t actually affect the end user experience. This can be removed if necessary to tidy up the link.

Affiliate Specific Parameters

AT – Affiliate Token: PHG’s affiliate token.

CT – Campaign Token: Also for PHG. This is a value to help you determine (or set) the “campaign” of the link (similar to the “Enhanced Publisher Interface” from Tradedoubler or the “Signature Tracking” from LinkShare). With GeoRiot, this parameter is set with the TRACK parameter and is synonymous with “Tracking Tag”.

TDUID – TradeDoubler Unique Identifier: This is used for affiliate links that skip the TradeDoubler redirect. For those links, this value is consistent per account but needs to be set up with Tradedoubler in advance.

partnerId: Previously used to identify each of the original affiliate networks, but currently only used for TradeDoubler, which has an ID of 2003. Note that the capitalization of this parameter is important.

affId – Affiliate ID: After a Tradedoubler link is processed via their redirect the final link will include the affid parameter. The value included will be the same as the “a” value in the original Tradedoubler affiliate link that was resolved.

Source

The mt = Media Type. mt=8 == media=software

Valid media types are : movie, podcast, music, musicVideo, audiobook, shortFilm, tvShow, software, all

presumably, movie = 1, podcast=2, music=3, musicVideo=4 and so on until software=8

I think anything other numeric value (>8) than those valid ones will return all.

I USED to think you could strip the mt and ls parameters without any impact.

I just discovered a case where that failed... it worked find on iPhones without the parameters but not on iPads. On an iPad it launched iTunes, but never brought you to the right app.

I m not sure why... but, I put them back in and it works fine on iPhone and iPad.

I didn t experiment with stripping just the mt vs. the ls. I suspect it s the ls=1 that is the culprit... though I m not sure why iPhone would be more forgiving than iPad.

The app on Appstore has specific URL format http://itunes.apple.com/[country-code]/app/[app-name]/id+[id_value]?mt=[1...12]

1. country-code can be us for united states, in for india etc
2. mt stands for Media Type

3. Value for mt can be anything from 1 to 12 and each assigned to specific category

   i. 8 for iOS apps

   ii. 12 for Mac apps

When you ve got a unique id already like: itunes.apple.com/us/app/rogo/id400118698?mt=8

it seems to work fine without it, ie: http://itunes.apple.com/us/app/rogo/id400118698

In this new URL format, only the id matters - the app name "rogo" is ignored.

Note that some browsers will respect preferences for handling different media types -- ie it can have unintended/unexpected consequences if you strip it.