A friend of mine posted his a few months ago and was promptly hacked.
If your friend's computer/network was insecure, it likely would have happened regardless of whether he posted his address publicly or not, and the fact that he did post it somewhere around the same time is likely just coincidence.
Most exploits these days are automated, run by already compromised hosts, and they tend to simply scan large network ranges, particularly known DSL and cable modem networks. If your system/network is insecure, you will be compromised eventually. If your system/network is secured (with the caveat that, of course, security is a process, not an end result) your chances of being compromised are slim, whether your IP address is widely available (eg, due to a forum post or something) or just slightly less available (eg, restricted the logs and stats of the hundreds of servers you touch daily).
If you want useful replies, ask smart questions.