Thats how most forums work, and I think it's a good system. Not only does it mean it's always up to date, but here on DP sig selling is big, and if I sell my sig link for a month, from a business point of view I like it that it only stays there for a month, then changes. Works well IMO.
ofcourse it's good. that why people can sell their sig links. or else we could not sell the sig links at all. right?