If you send @ messages to a large number of people, that's spam, by definition. They don't have to visit your profile to see that. Some of them will just "flag" you if you send them unsolicited @ messages, and you can, and will eventually, be banned from Twitter.

There is no other (legit) way, in my view. If you want to send messages to a large number of people, then you'll have to build your audience/followers over time.

PS: Here's an article I wrote a few weeks ago, if you are interested: http://blog.tweetdelegate.com/post/21164614504/how-do-you-ge...