With the business cycle theory of investing, I don’t worry about daily returns and generally only care about anything shorter than a month out of curiosity. But for the website updates I do feel like I need to provide some hard numbers, so thankfully there are some other sites which provide those.
I typically get my Year-to-Date and other date range numbers from TSPcenter.com.
The nice folks at TSP Center are very into technical analysis so they worry about what the funds do every day and have some handy tools as a result. They also generally have a very friendly, supportive forum with very few of the keyboard bullies you so often find online. When I have a spare minute in the elevator I sometimes browse to see what folks are talking about there (mostly Bollinger bands, moving averages, and the like), but usually flee in a panic when I see how often they are trading.