Most of us have more than one email account. Even if you do not, I would strongly suggest you to keep a second account(what I call a temporary account) which you can give as a reference to many forums that ask for it. You need not think twice about the spam. It is not going to affect your primary account. Managing multiple accounts is sometimes very cumbersome. Gmail has come up with a really nice solution to this in the form of Multiple Inboxes.
Given below are the steps to manage your secondary accounts from your primary Gmail account.
To enable Multiple Inboxes,
1. Go to settings in your Primary account.
2. Under the Labs tab,enable multiple inboxes.
Now in your secondary account,
1. Go to settings.
2. Go to the Forwarding and POP tab.
3. Enable forwarding and forward all mails to your primary account.
Now log in to your primary account again
1. Go to Settings.
2. Go to Multiple Inboxes tab.
3. type “to: <your secondary email address>”
4. You may also create inboxes such as “is starred”, “is drafts”.
That’s it. All forwarded mail will show up in the secondary Inbox. You could also use the “superstars” feature in Labs to categorise your mail aptly (I use Green stars for my temporary account).