One of my routine considerations, is the amount of time I invest in websites that I own, versus the amount of time I invest in the websites of others.
In many cases, that boils down to the value of domain ownership – websites, blogs, and so forth. Sites where there is little question to who benefits, and if you do good things, the asset grows in value. I still believe in these types of websites. In my own little Maslow pyramid, they set the foundation and I see little value in pushing ahead without them.
But the question then becomes, what's next? Even if we own our websites, who's reading? who are we connecting with? One of the reasons I don't have an issue with participating in Twitter or social networking sites is because these tools are 1) good for feedback, and 2) solid distribution channels. And while feedback is extremely important, distribution channels are becoming, in my view, almost critical.
Unless you have a pre-existing audience, a solitary writing routine isn't going to cut it. Some channels are low lying fruit, available for the cost of participation. I put social networks (the 'garden wall' variety) in that class, along with Twitter, JD Supra, and RSS. If you have content to feed them, you'll get value back.
There are also channels that require more work – email marketing and search engine marketing are good examples. Building a collection of email subscribers who value your content (& don't think you're a spammer) is no easy task. Same goes for search marketing, where on-page optimization is rarely enough. A website needs a strong & diverse link network to rank well, with the best links based on relationships or endorsements of your published content. Both these tactics may have a high ROI, but are often deceptive in the amount of time required, and the number of human relationships involved.
The last point I'd like to make, is the required interaction between tools. Some we will own, and some we sign-up for, but together they should be judged as a team. Not measured individually. Don't like your results? Change what you're feeding the channels, add new channels, or automate those that don't perform.
I pay attention to content routes, destinations vs channels, link citation and the value of incoming links, authenticity of message, the audience, and the feedback. I also try to balance my time so I value personal publishing (read: sites I own).
If someone's got an ROI formula for all that, I'm happy to take a look.