xmarks是firefox的一个插件，它的原名叫做foxmakrs。
    安装xmakrs后，只需要在它的网站注册一个账号，你收藏的网站就会定期备份到你的账号中。这样就可以方便的备份你的收藏网址了。
    在你收藏某个网站的时候，它会根据别人收藏该网站时使用的标签，给你推荐一个使用人数最多的标签。
    由此，它给出了我认为最好的一个功能：在你使用google进行搜索的时候，它会自动在google的每一个搜索结果后面，加上一个该搜索结果在相关领域内收藏次数的名次。
    以我的搜索：UML为例，它就会在每个google的搜索结果后面给出其在xmarks中被以UML标签收藏的次数的排名。由此我就能很容易的发现，argouml是被人以UML标签收藏次数最多的网站，所以我想argouml应该就是我想找的最火的开源UML建模工具

Tab and window shortcuts

Ctrl+N	Opens a new window.
Ctrl+T	Opens a new tab.
Ctrl+Shift+N	Opens a new window in incognito mode.
Ctrl+B	Toggles the bookmarks bar on and off.
Press Ctrl+O, then select file.	Opens a file from your computer in Google Chrome.
Press Ctrl and click a link. Or click a link with your middle mouse button (or mousewheel).	Opens the link in a new tab in the background .
Press Ctrl+Shift and click a link. Or pressShift and click a link with your middle mouse button (or mousewheel).	Opens the link in a new tab and switches to the newly opened tab.
Press Shift and click a link.	Opens the link in a new window.
Ctrl+Shift+T	Reopens the last tab you've closed. Google Chrome remembers the last 10 tabs you've closed.
Drag a link to a tab.	Opens the link in the tab.
Drag a link to a blank area on the tab strip.	Opens the link in a new tab.
Drag a tab out of the tab strip.	Opens the tab in a new window.
Drag a tab out of the tab strip and into an existing window.	Opens the tab in the existing window.
Press Esc while dragging a tab.	Returns the tab to its original position.
Ctrl+1 through Ctrl+8	Switches to the tab at the specified position number on the tab strip.
Ctrl+9	Switches to the last tab.
Ctrl+Tab orCtrl+PgDown	Switches to the next tab.
Ctrl+Shift+Tab orCtrl+PgUp	Switches to the previous tab.
Ctrl+Shift+Q	Closes Google Chrome.
Ctrl+W or Ctrl+F4	Closes the current tab or pop-up.
Click a tab with your middle mouse button (or mousewheel).	Closes the tab you clicked.
Right-click, or click and hold either the Back or Forward arrow in the browser toolbar.	Displays your browsing history in the tab.
Press Backspace	Goes to the previous page in your browsing history for the tab.
PressShift+Backspace	Goes to the next page in your browsing history for the tab.
Click either the Back arrow, Forward arrow, or Go button in the toolbar with your middle mouse button (or mousewheel).	Opens the button destination in a new tab in the background.
Double-click the blank area on the tab strip.	Maximizes or minimizes the window.

Address bar shortcuts

Use the following shortcuts in the address bar:

Type a search term, then press Enter.	Performs a search using your default search engine.
Type a search engine keyword, press Space, type a search term, and press Enter.	Performs a search using the search engine associated with the keyword.
Begin typing a search engine URL, pressTab when prompted, type a search term, and press Enter.	Performs a search using the search engine associated with the URL.
Ctrl+L	Highlights the URL.
Ctrl+E	Places a '?' in the address bar. Type a search term after the question mark to perform a search using your default search engine.
Press Ctrl+Shift and the left arrow together.	Moves your cursor to the preceding key term in the address bar
Press Ctrl+Shift and the right arrow together.	Moves your cursor to the next key term in the address bar
Ctrl+Backspace	Deletes the key term that precedes your cursor in the address bar
Select an entry in the address bar drop-down menu with your keyboard arrows, then press Shift+Delete.	Deletes the entry from your browsing history, if possible.
Click an entry in the address bar drop-down menu with your middle mouse button (or mousewheel).	Opens the entry in a new tab in the background.
Press Page Up orPage Down when the address bar drop-down menu is visible.	Selects the first or last entry in the drop-down menu.

Webpage shortcuts

Ctrl+P	Prints your current page.
Ctrl+S	Saves your current page.
Ctrl+R	Reloads your current page.
Esc	Stops the loading of your current page.
Ctrl+F	Opens the find bar.
Ctrl+G or Enter	Finds the next match for your input in the find bar.
Ctrl+Shift+G orShift+Enter	Finds the previous match for your input in the find bar.
Press Alt and click a link.	Downloads the target of the link.
Drag a link to bookmarks bar	Bookmarks the link.
Ctrl+D	Bookmarks your current webpage.
Space bar	Scrolls down the web page.
Home	Goes to the top of the page.
End	Goes to the bottom of the page.

Text shortcuts

Ctrl+C	Copies highlighted content to the clipboard.
Ctrl+V or Shift+Insert	Pastes content from the clipboard.
Ctrl+Shift+V	Paste content from the clipboard without formatting.
Ctrl+X or Shift+Delete	Deletes the highlighted content and copies it to the clipboard.