Problems with twitter

1. Twitter needs meta-data. Using up your reply text area for "#", etc., and now location data is just becoming too restrictive.
Meta-data future?

2. Twitter needs location information associated with each tweet (if it's available or configured into the user agent used) (see [1])
Location info, 
More Location info
 

3. Why is twitter restricting message length? They should sell the capability of sending longer messages, thus making money. 

4. There's no way to link up replies with the original tweet. Each tweet has a unique number, so this should be trivial, however... see [1].

5. There needs to be a way of specifying that a tweet should go to a "group" of people you have defined, or should be sent to everyone except a "group" of people you have defined. (see [1]).

6. Twitter needs to be able to include URL into a tweet via metadata. Why not just use the various services which allow you to shorten a URL? Because it's insecure! When you click on that URL someone else sent in a tweet, you don't know where it'll take you! This is an extremely big security hole! Metadata would solve it because Twitter applications could then display the URL to which you will be taken in the same way they do now in browsers. Since long URLs would no longer use up message text length, including one or more of them would not be a problem. 

7. Many companies (and individuals) will follow a person on Twitter hoping that the person will follow them back such that the person will then receive their ads. This is a problem for Twitter because it adds to the overhead on their servers by sending thousands of tweets to such company or individual accounts when they're really not interested. Metadata would solve this by allowing such companies to send out a message which clearly asks the person to follow them and even allows a one-click response to do so! Once again, this could be an additional for-pay service, since mostly companies would be using it. Providing it would save a lot of unnecessary overhead on Twitter's servers as well. Need I also mention that this would address the Twitter "follow-me" email Phishing attack (see the Twitter security article above). 

8. Twitter could become the first of a new way of advertising! Imagine being able to actually search out ads for an item, or a type of item, which you would like to buy. If you're thinking of purchasing a new flatscreen TV, imagine being able to search through Twitter messages for any notes about flatscreen TVs, what people liked, what people hated, what deals are out there, and even ads from companies? "Pull" advertising, where the customers actually want the information instead of more of the same old "Push" advertising which everyone hates. 
I'm sure there are others. Anyone want to add a few?