You are a great service, providing facilities to those of us who like to micro blog in 140 characters or less. You have grown to massive amounts, and I am glad for your success, as I have made several friends through your service, however, I am of the opinion that you keep adding unneccesary bloat to your unique service, trying to be like the other social media sites.
The reason so many like your service, is that it is fast, has a good API, and isn't loaded with many features we're never gonna use. Twitter is NOT Facebook, and hey, I know you're the ones with the business model, but I personally don't think that you should aspire to be.
First you add retweet integration, which is awesome, build on something invented by the community, loving it, it's this type of attitude which makes twitter so great, as it seems that you actually listen to your users..
Then you add lists, which is cool for some, we can add friends to certain lists, follow entire lists, okay, this is kinda cool, though it's a use it then forget it feature, I know that I, a daily visitor to your site, certainly haven't used lists more than once, and so don't see the repeat appeal.
Now I see you're adding a "local trends" feature, yet you're obviously aiming it towards the US, as I only see three european countries on this list. If I wanted to get the local trends, I'd do a search on twitter or google, or go outside and read a newspaper, to paraphrase someone on IRC "I wouldn't be on the net if I cared what was going on around me".
Why have I written this? Because I see this danger of Twitter becoming bloated, and slow, like myspace or facebook, and I just hope that this wont happen.
Esteemed Regards, Mikey Mikeylicio.us