I recommend not using WebClient.DownloadString. This is because (at least in .NET 3.5) DownloadString is not smart enough to use/remove the BOM, should it be present. This can result in the BOM () incorrectly appearing as part of the string when UTF-8 data is returned (at least without a charset) - ick!
Instead, this slight variation will work correctly with BOMs:
string ReadTextFromUrl(string url) {
// WebClient is still convenient
// Assume UTF8, but detect BOM - could also honor response charset I suppose
using (var client = new WebClient())
using (var stream = client.OpenRead(url))
using (var textReader = new StreamReader(stream, Encoding.UTF8, true)) {
return textReader.ReadToEnd();
}
}