You can't resize the Web clip. If it's large, it's likely to take up much of Dashboard's screen. Also, if you delete it, it's gone rather than moved to the Add Widgets screen. If you want it back, you must re-create it using the steps I've just outlined.
You can customize the clip's frame and the size of its content area. To do that, hover your mouse over the clip and click the i button. When the clip flips around, you'll see that you can choose from six different frame styles. Pick the one that suits you and click Done.
If you find that adding a frame cuts off content that you want to see, click the i button again, click the Edit button in the resulting window; when the clip flips back around, click and drag in the middle of the clip to change its content's position, and click and drag the bottom-right corner to expand or contract the size of the clip's content area. When you're content with your work, click Done.
And that's Dashboard, an often overlooked feature of OS X that gives you quick access to tidbits of information and helpful tools.
Next week: We go on Safari
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