If you’ve been following the Twitter (s twtr) rumor mill at all, you’ve probably seen reports about a number of things that the company is trying out — as part of its ongoing beta testing of new features, which it has a policy of never discussing in public — or is said to be thinking about, including getting rid of @ mentions, doing away with hashtags and changing “retweet” to “share.” On Wednesday, it added a feature that allows users to tag people in photos without using up any of their 140 characters, and to add up to four photos to a tweet.

There are a number of factors driving these experiments, but more than anything, the goal seems to be to find a way to cram as much stuff as possible into 140 characters. The very brevity that was Twitter’s claim to fame — and arguably helped drive…