Simple example of a key-mapped Sublime Text snippet (⌘+b for bold)

bold.sublime-snippet

<snippet>
	<content><![CDATA[
<strong>${TM_SELECTED_TEXT}</strong>
]]></content>
	<scope>source.html</scope>
</snippet>

Default (OSX).sublime-keymap

[
    { "keys": ["super+b"], "command": "insert_snippet", "args": {"name": "Packages/User/bold.sublime-snippet"} },
    // Set context so shortcut works in HTML files only
    { "keys": ["super+b"], "command": "insert_snippet", "args": {"name": "Packages/User/bold.sublime-snippet"},"context":[{ "key": "selector", "operator": "equal", "operand": "text.html" }] }
]

Add the snippet to your Packages/User folder and then go to 'Preferences' > 'Key Bindings – User' to add a keyboard shortcut.

You can set the context for the keyboard shortcut, so it only works in certain scopes. See the example above for a simple implementation. The beauty of the scope context is that you can limit it from being HTML right down to a paragraph within a section element for example.

You'll want to use something like ScopeHunter to find the scope.

Check the key bindings docs for the operator and operand settings. With those regex options you can do anything!