Most marketers tend to equate email unsubscribes with failure. While this is understandable (unsubscribing is a form of rejection, and nobody wants to see their list get smaller), continuing to send email to someone who has lost interest is generally not a good idea. As a matter of fact, continuing to send email to someone who has taken the express action of unsubscribing is illegal in most countries, including the US.
Unsubscribes do not have a negative effect on your email sending reputation. In a sense, they’re a type of list cleaning, as unengaged people are being taken off your list – they are no longer going to ignore your emails. However, there are ways, and things you can do, to keep your recipients engaged and minimize your unsubscribe rate. And you should be glad and thankful that those unsubscribes didn’t come in the form of putting your email in the junk folder, which ISPs note as a spam complaint.
It is required by the CAN-SPAM Act that all commercial messages received by recipients in the US must include the option for recipients to opt out of receiving email and this offer must be clear and conspicuous. Trying to hide your opt-out link is always a bad idea; if someone wants to unsubscribe and can’t find it, it’s really likely your email will get marked as junk.