You probably won't have trouble getting in to other people's mailboxes anymore than if you had the email
email@example.com. Most (all?) filter programs can't distinguish between
firstname.lastname@example.org, provided that you have your email server set up correctly.
That being said, don't reinvent the wheel if you don't have to. Gmail has this kind of functionality built in, simply add a
+ after your real email address, followed by an arbitrary string of characters:
Then, you can filter messages from this domain in whatever way you wish. Go to account settings -> filters and add a filter for emails that are "To:" the newly created e-mail address.
However, there is a caveat with the above technique: some sites, whether intentionally or by accident, do not accept emails with a
+ in them. Thus, you might think that you have to give over your email to this scummy site that does not accept your
+. Although this is obnoxious, because you can no longer use an arbitrary string of characters to identify the site, it is still workable. Gmail allows you to have an arbitrary number of dots (
.) in arbitrary locations in your email address without affecting the "actual" email address. That is to say:
Is going to end up in the same mailbox as
Using this technique, you can generate "random" email addresses for scummy sites, even using the site name in the new email if the website allows all proper email addresses. If the website disallows
+ in email addresses, then you can add dots in random locations in your email in order to generate a "random" email. However, in the latter case, you have to keep track of where the dots are for which sites.