In the race for users and revenue, Twitter has unleashed a collection of changes--many designed to attract marketers. Here's a recap of the major changes this year to date so you don't have to hunt around.

Vine launched. (January) Vine is a simple to use micro-video (six seconds, to be exact) filming app disseminated through Apple's App Store. "Vines" loop and can be produced and tweeted instantly. Vine content has become digital users' newest obsession.

Improved photo, video and related-conversation viewing. (January) Click-to-enlarge photos shown on profile pages or search results. Video content is now also included in a user's media gallery and expanded tweets. Tweets related to an original tweet are pulled in to directly show conversation and context.

Twitter Ads API. (February) Twitter opened up its Ads API and partnered with companies to help marketers more easily manage their Twitter ad campaigns.

Older tweets in Twitter search results. (February) Instead of just showing tweets a week old or less, through an algorithm that evaluates "a variety of types of engagement, like favorites, retweets and clicks," Twitter began to incorporate relevant older tweets into its search results.

Improvements to self-service ad tools. (March) Improvements included targeting by users with the same interests as followers of @usernames or a list of 350-plus interest categories and access to Twitter's advanced interface which enables "deeper campaign controls, detailed reporting and analytics, and multi-campaign optimization."

Updates to Twitter Ads center. (March) Improvements to campaign analytics reporting and insights.

 Keyword targeting in Timelines. (April) Advertisers can now target users based on the keywords in their recent tweets and the tweets with which users recently engaged.

Revamped Twitter for Business launched. (April) More help for businesses looking for ways to market and advertise their business through Twitter.

Twitter #Music. (April) Making a play at audience expansion, Twitter rolled out its new music service that uses "tweets & engagement to detect and surface the most popular tracks and emerging artists."

TV ad targeting. (May) Beta test for national TV advertisers to synchronize, extend and enhance TV ad campaigns.

Lead Generation Cards. (May) A direct response tool built into an expanded tweet that makes it easy for users to immediately express interest in a brand offers.

More and Longer Twitter Lists. (May) You can now make up to 1,000 Lists (up from 20) and each list can include up to 5,000 accounts (up from 500). Think about this for prospects, clients, favorite sources of news and information, and other segments worth tracking.

Login Verification. (May) After multiple account hacking scandals, Twitter enhanced its login security with improved authentication.

Twitter sunsets popular TweetDeck phone apps. (May) Perhaps it was inevitable. One year after purchasing the popular TweetDeck application, users of its phone app version had to migrate to a different Twitter phone app.

Twitter for Google Glass. (May) Maintaining its edgy cool, Twitter enables users of Google Glass to share photos and receive notifications.

Vine for Android phones now available. (June) And we've come full circle! Vine can be downloaded from Google Play if you have an Android phone. Once you have the Vine app, look me up by my Twitter handle (@hollisthomases) and view the special Vine I made just for this article!