Unlike a lot of top 5 lists around these days I would like to take a different approach, and thereby taking exception to a lot of the top 5 lists around these days, no offense. :+)
We all use SM for different reasons. I learn so much from my contacts on LinkedIn, Facebook and Twitter that if I were to give you things I don't want you to tweet about, I might miss something really cool.
So here's my list of what I want to read:
1. New and hot bloggers - please keep telling me who you're reading. I often go visit and have found some extemely interesting business perspectives/tips/tricks. Don't stop touting interesting people (or people to follow/friend/fan).
2. Work projects - if you are working on a project that someone out in the SM world could help you with...don't hold back - collaboration is one of the key things SM give us access to!
3. Great restaurants - while I often get hungry, and therefore sometimes angry, when I am not eating delicious food like you - I still want to hear if you're having a fantastic meal and where. It expands my knowledge base and gives me options of places to try.
4. Photos of your vacation, dog, cat, baby, husband, wife, friends, etc. - while we are connected to each other through SM we don't see each other F2F very often, if ever, so if you stopped posting photos of personal interests that are important to you we might not ever get a chance to learn more about you, find more commonalities between us, and therefore build a stronger relationship with you.
5. Interesting news - even if it's not industry related, you never know where you will get the inspiration for your next big idea. Post it especially if it's industry related...we all want/need to know - don't hold back.
For me SM gives me an opportunity to meet and connect with interesting people - if you stop doing the above because someone created a list that said you should stop doing these things, most likely I would stop following you because I wouldn't believe there was a person behind the name...