Twitter

The website which you can be accessed is: www.twitter.com

Twitter it is a social web, where you can post messages shorter than 140 characters long, you must have an account and it is free.
Everything you post to Twitter seen it all.

Advantages:
- It is generally a simple tool once overcome the first print 

- Constantly dynamic, not only for the replies, but for the RT and even Trending Topics;
- It has a multitude of applications that enable its expansion;
- It is, in itself, a catchy name with a much more catchy logo;
- It is relatively editable, allowing customization to suit the user. More editing, more comfort

 Disatvantages: 

- It became popular very quickly, leading to a depletion of content (which was innate but is enhanced)

- Twitter leads to less and write more abbreviate to get to 140 characters

- Breeding ground for spammers, which usually come in English (and bad from the factory)

- The default language is English Twitter, users having Spanish-speaking
- Lack of tools to include the common user to this new system

Alternatives:  

1. Co-op

2. Cynapse

3. Jaiku
4. Obayoo
5. Presently
6. Sharetronix
7. Snipia

8. Socialcast

9. Socialtext 
10. Status.net 
11. WorkSimple
12. Yammer