I’ve been inundated with Twitter clients to review lately. After using so many applications, I got to thinking about what features I expect from a Twitter client. Some features are more important than others, so I’ll break them down into three categories: essential, would be nice and optional.

‘Essential’ Features

• Replying – This could be done via a link or button, but it must be included in some way, shape, or form other than typing @microblink. I consider replying to be one of the basic Twitter functions.
• Retweeting – What good is a social network if you can’t spread the word? Similar to reply, you must also be able to click something and have the retweet text entered automatically. Formatting for the text would be nice to have, but is not essential.
• Multiple views – Nobody wants to sift through their timeline to find a direct message or reply, so they need to be broken down into categories.
• Play nice with external links – If there’s a link in a tweet, make sure users can click it and have it open in their default browser. Also, link to any users (ie @chewbocka) and any hashtags (#dmtweetup) in tweets.
• Friend management – Every client needs to have the ability to easily follow and unfollow users as well as look up their profile information. Profiles can be linked to, but friend management must be done within the client itself.
• URL shortening – Since we’re limited to 140 characters on most networks, each character becomes that much more important. Services like is.gd and tinyurl.com shorten your long URL into one that’s generally 20 characters or less. Developers must provide simple, intuitive ways to do this through their clients.
• Feedback – I simply cannot stress this enough. Too often I’ve posted a tweet and get no response from the client that it acknowledges my tweet went through. Provide helpful error messages and status updates when something is going on.
• Innovation – Build a client that makes users want to use it. If you’re rehashing work someone else did, improve on it. Try pushing the boundaries of innovation a little. Who knows, you might end up like this guy.

‘Would Be Nice’ Features

• Notifications – Myself included, many people can be obsessive about checking for new tweets. Trust me, you’re doing us all a favor by telling us when new tweets have arrived. Along the same lines, small alerts that are non-intrusive work best. Also, let us turn them on and off as we deem necessary.
• Favorite tweets – I generally don’t favorite any tweets, but there are people who do it quite often. At minimum, provide a way to favorite a tweet. If you can work it in, show us our favorites.
• Searching – More clients need to embrace the power of search.twitter.com. It’s fast, it’s easy, and it’s very useful. There are already a good number of clients that use Search, but I feel that more should.
• Member Grouping – One user (@ku5h) thought it would be nice to be able to categorize members into groups and then send a message to the whole group. For most people, this probably doesn’t happen very often, but it would be much easier than trying to hash your posts so a specific set of people would see it.

‘Optional’ Features

• Timestamp formatting – Some prefer to have their timestamps show up as relative (2 hrs ago), but others prefer to have them show as absolute (12:00:00 Sep 3 2008). A great Twitter client would provide flexibility in displaying timestamps.
• Integration with other networks – It’s more common now to see Twitter clients that support outside services like Identica, FriendFeed, Seesmic, etc. I don’t think we need the level of functionality ping.fm provides, but it’s nice to be able to send to multiple networks at the same time. My advice: use where appropriate and use sparingly.

In my experience with third-party clients, there’s no single client that has everything I’m looking for. Some come close, but still fall just short. As always, client ratings are generally based on need and preference, so you may or may not agree with what I feel are necessary features.

One thing all Twitter clients absolutely must have is a feature set that will draw users away from the web interface and, more importantly, other clients.