TweetLater, the tweet-scheduling Twitter service that also brought users the ability to auto-follow and auto-welcome new followers, has released two new features this week in an attempt to help users better manage their accounts.

Keyword Monitoring Made Easy

Though keyword tracking via IM was one of Twitter’s most popular features back when it was available, there haven’t been many good solutions for staying on top of microblogging keyword searches lately, unless you’re pulling RSS feeds based on Twitter Search queries. Dewald Pretorius, creator of TweetLater, decided that he’s tired of waiting for track to come back to Twitter and has developed his own version of the service as an added feature inside TweetLater.

Pretorius’s version is not exactly the same (he’s using email instead of IM), but it will help you stay on top of the keywords most important to you. In your TweetLater account you can set up keywords and phrases to be monitored in the public stream on Twitter and it will periodically send back a digest email with tweets matching your queries. As I mentioned, you could do something similar to this with RSS and Twitter Search, but TweetLater allows you to monitor as many keywords as you want, all in one delivery, instead of multiple RSS feeds.

The keyword alerts work much like Google searches, using quotations to search for an exact phrase, though TweetLater also mentions that “you can use any of the operators that are supported by Twitter Search.” Also, the digest email will only send back the last 100 tweets from your query, so monitoring busy keywords with this service may not give you the entire picture.

Managing @Replies Just Got a Whole Lot Easier

Twitter is doing well these days with not dropping tweets and @replies, but there always seems to be one pesky day where you miss out on people trying to get ahold of you. Even in apps like Twhirl it’s easy to miss @replies, mostly because you’ve got to have it running if you want to be notified.

Dewald’s second new feature for TweetLater is what he calls the @Reply Digest, a query similar to his keyword search that will monitor the public stream for @replies to your user account and send you a periodic email with all of those messages. This tool could be a great way to manage @replies from a to-do list perspective, because you could mark messages as read or leave them unread until all messages have been replied to or filed.

If you’re not already using TweetLater to schedule tweets or send auto-welcome messages to new followers, you’ve got to check them out for monitoring your favorite keywords and @replies.