Its a major SEO tactic, if you don't get involved someone else will, and as long as you have an interesting perspective on the case and add value to the discussion, you are contributing rather than doing anything wrong.

Take this post: http://news.ycombinator.com/item?id=1900735 this is something I have just submitted but I am adding value in the article, it is relevant to HN visitors and the case scenario has historical video footage to detail a current event company goes into administration (Video shows the reasons why the company went into administration) which was made 1 year ago and well before these events.

but since its a 'current event' - surely the SEO value is very time constrained?

Also, i didnt really mean writing about it, I actually meant DOING it. so in this example - is AOL being dirty by hijacking Facebook's email launch? Do they look bad by trying to launch a few hours before Facebook?

I don't know if it's perfect. What if the thing that you're trying to hijack the hype of eclipses yours? If the media are only going to write about one thing today and yours is second best, why would they write about yours?

If it's marginally related the story can read: "Two Companies Take on Gmail" And then you can run a story on how the war for e-mail is heating up. If only one company does it, it's not a trend. So the hope is that you get caught up in a trend, not just the Facebook vs google story.