Here's a couple of examples of interesting signatures.
Notice the handmade bisque stamp with the marks on the jug at the left.
I'm not so sure I would want a face under the handle of a jug, but you have to admit, once seen, not forgotten quickly.
This philosophy is a basic idea of advertising; make your product/pitch/impression memorable.
If you think about it, you really DO want the public to recognize you and your work. At least in this world, at present, the concept of product branding is so prevalent in our culture, it has become an integral part of selling your work.
Along those lines of thinking, I once read a suggestion that an artist should also include the town you live as part of your mark. That people will buy local artist's work as a memento of a trip or as a gift for family members or friends. I'm not so sure I want that to be the basis of why someone buys my work: To be classified as an interesting souvenir, but then, who can know the mind of every customer. People buy things for all kinds of reasons and I'm there to sell my work, right?
I'm also not sure that will make it more likely a piece would sell, but it might be worth considering....especially if you happen to live and work in a vacation spot or notable place.
So, back to stamps: This is an exceptionally nice custom made stamp.
I have seen these at the commercial exhibit at NCECAs and many people swear by them.
Having your own stamp made is not cheap, but I doubt you would need any more than one. The impression is very nice and crisp.
Check out his website at http://www.claystamps.com