Most legislative offices have adequate staff resources to respond only to their constituents.
The inclusion of your full name and mailing address will allow your legislator to determine if your residence is within his or her legislative district. Naturally, when sending email to members of a committee, send individual email to them and indicate that, as a Washington State citizen, you wish to communicate with them. In this case, put the mailing address at the end of the message, as they may otherwise trash it. Remember, a personal letter is worth 10 phone calls. A phone call is worth 1 fax or 1 email.