Productivity: Three top daily time wasters

What are your top 3 time wasters and what's the solution / recommendation to limit the wastage?

1. E-Mail: Do this in 30 min time-bursts 2 or max 3 times a day. I have experimented this and it works like a charm. Just need to get more disciplined and do this more regularly.
2. Social Media: Stick to specific times a week (say 2-3 times) when you spend a max 30 mins connecting with friends and family on Facebook, LinkedIn and other Social Media channels.
3. Meetings: When you get an invite, see what is the worst thing that can happen if you skip it. My super-boss made this recommendation last week. You should attend a meeting only if you are chairing the meeting or are going to talk in the meeting (for more than 10% of the time)? If the answer to both is no, you can probably skip it 90% of the time. Additional Rules: Can you avoid the meeting by sending out an e-mail with your thoughts or talking to the meeting co-ordinator for 5 mins after the meeting. How important is your role there? Use these above guidelines to skip a meeting today and gain 30 mins of your life back.

Source: http://the99percent.com/tips/7019/The-Top-3-Daily-Time-Wasters-How-To-Tame-Them