I guess it depends whether OP made their service as startup looking for a great exit, or a passion project based on their hobby that got extended to their friends.
Personal or business it doesn’t matter. If you met your friend for coffee and they told you they are pregnant (for example) would you feel emboldened to post on Twitter congratulations without even asking her if she wants the world to know?
I get that this was 2003 but if anything it would have seemed even more rude before social media made posting about your life online more acceptable.
But to use your analogy, if my friend invited a few hundred people she knew and told us she was pregnant, then yes, I would feel fine posting about it on Instagram.
The difference is that the pregnancy doesn’t affect the lives of all the people on Twitter. This guy was communicating with his clients, who had to respond to the news by working to prepare their albums for upload to iTunes. He had a perfectly legitimate reason for posting this on his website.
