A few days ago, we reviewed iTwitter, one of the earliest iPhone 3.0 Twitter apps to support push notifications, but one major let-down of iTwitter is that push notifications only work when both parties use the iTwitter client. Today, however, Boxcar arrived in the App Store (iTunes link), and this client actually polls your Twitter feed every 5 minutes and sends out push notifications whenever a new direct message or @reply arrives. Messages sent between Boxcar users will be pushed out immediately.

Not a Fully-Featured Client

It’s important to note that Boxcar is not a fully-featured Twitter client. While you can reply to direct messages right from the app, it will actually open up your favorite Twitter client (you can currently choose between Tweetie and Twitterific) in order to open up replies. In the next version, which has already been submitted to Apple, Boxcar will also give you a choice to handle your direct messages in another Twitter client as well. This new version will also support multiple Twitter accounts.

OAuth Support

One nice aspect of Boxcar is that it allows you to sign in to your Twitter account using Twitter’s OAuth implementation, which means that you won’t have to give your Twitter name and password to yet another company.

Of course, Boxcar’s 5-minute delay is still not quite the instant push that some users would like to see, but chances are that we will see this in the near future. At that point, Twitter could become a real alternative to sending text messages to your friends (assuming your friends are on Twitter and have a phone that supports push messages, of course).

We should also note that IM+ (iTunes link), which is mostly an IM app, but also supports Twitter, can also send push notifications when you receive direct messages and @replies. If the IM functionality isn’t of interest to you, however, or if you don’t want to switch away from Tweetie or Twitterific, Boxcar is probably a better solution at this time.

Boxcar as an Infrastructure Service

Overall, we think Boxcar is a very interesting solution, and at $2.99, it is also a dollar cheaper than iTwitter. We especially like the fact that, at least at this point, Boxcar is basically providing an infrastructure service and allows you to continue to use your favorite Twitter apps just like you used to.

frederic lardinois