A thousand pardons if this has been discussed before. But if not, I figure this might be a good topic to discuss in light of a recent thread here. Favor, though: please make sure you've thought long and hard your potential answer before posting. While discussing and debating is healthy, let's try not to add any more junk to the 'net, shall we?
Here is my two cents, but it is only applicable to the US. So, if you live elsewhere, this will be interesting but not useful. The governing laws in the US are the Uniform Electronic Transactions Act of 1999 which was signed by 46 states (including California) and the U.S. E-Sign Act of 2000, which is Federal legislation. Both laws share certain definitions: ELECTRONIC - The term `electronic' means relating to technology having electrical, digital, magnetic, wireless, optical, electromagnetic, or similar capabilities. ELECTRONIC SIGNATURE - The term `electronic signature' means an electronic sound, symbol, or process, attached to or logically associated with a contract or other record and executed or adopted by a person with the intent to sign the record. What these laws state essentially is that if you have some method for people to signify that they are who they say they are (this can be a simple submit button) then it is a binding signature. These laws are not applied in a standard fashion in all areas of the country. However, various courts in the U.S. have extended this to e-mail. Electronic Signatures are not to be confused with Digital Signatures which require encryption and a higher standard of ensuring the person is not spoofing the account. Electronic signatures are legally binding. If a person can prove that their information was spoofed they will not be held liable. Short of that, it is the same as if they inked it with a pen. Also, I noticed the about page on your site has a typo: ties to eep abreast I believe that should be keep
My opinion is that a contract is an agreement between two people. Technically that agreement could be verbal and still be "valid." However, verbal contracts make up the majority of plaintiffs So, I think a written contract over email holds up a heck of a lot better. Even though it doesn't necessarily have a notarized ink signature, it's much better protection than verbally. However, you have to make it sound very final and official. An email can be taken way out of context. Especially if its following up an online instant message conversion. It could be considered just a negotiation/offer as opposite to an absolute/final contract agreeable by both parties. If people are making email contracts without signing, they should at least make the other party "confirm that they agree" by replying with their name to show that it was an agreement rather than a negotiation. So, I don't think its the best idea... But it's sure of a lot better than having 0 protection.
It may be valid, but contracts are fact sensitive, it depends on whether or not other requirements are met. For one thing you have to have a meeting of the minds, you have to have consideration, you have to have an offer, you have to have acceptance, the parties also have to be competent. This is under US Law and things may be different in other countries.