If I left every one on there there would be so many I wouldn't be able to find anything.
Adobe Acrobat Reader has just done it. What on earth makes Adobe think it'd be useful for me to have it there? A link to Acrobat itself may be of use, if you want to create a new document, but reader? Nah!
If it's product placement that'll really piss me off. All it does is annoy me and make me want to avoid their stuff. (I'm not very impressed with their software anyway, and this just makes it worse).