I've made a browser extension that allows user to subscribe to any kind of tags.

Features:

• Extension adds "OwO/XwX (Subscribe/Unsubscribe)" button for every tag shown on the left sidebar
• Extension also adds "Watched" button to the navigation bar on top of the page. Clicking it activates special code that shows result as search query with every your tag OR-separated (even if there is more than six forty of them)
• List of watched tags can be checked from browser button
• It is possible to check new images without visiting the site via popup window -- it shows count of new posts since last visit
• ^NEW You can subscribe to complex search queries by entering them in popup window

Downloads:
Get for Firefox
Chrome Web Store