"Websafe" means that the colors will display true on most platforms, monitors and browsers. It used to be 216, back when monitors had only 8-bit resolution. According to the Oct 98 GVU survey, an overwhelming majority of users viewed from at least 24-bit monitors and that number will only increase. I switched to 4096 some time ago but some designers want ALL people to see pages as they designed them, so continue to use the 216-color palette.

Minimum 750 pixel width.

According to the Oct 98 GVU survey, most users viewed from at least 800x600 monitor resolutions. So I set my target dimensions for layouts to 750x430 — a bit less than the resolution to account for browser toolbar, scroll and status bar. My comps are 750x430 and if I use fixed table widths, set the width to a maximum of 750 pixels to avoid the horizontal scrollbar.

Border backgrounds at least 1600 pixels.

Monitors are getting larger and larger but the typical user's computer monitor is a maximum of 1280x1024. Setting image backgrounds that shouldn't repeat to 1600 pixels wide prevents the image from tiling where it shouldn't.

Maximum of 3 clicks to reach a subpage.

Usability studies show that information structures that are more than 3 levels deep is confusing to most users. If a deep structure can't be avoided, provide a site map.

Descriptive title tag and specific meta tags.

Use "keywords" and "description" attributes to help search engines find and rank the site. Keywords should be the words that users will most likely use to find the site and product/service. Most search engines limit descriptions to 250 characters, including spaces and punctuation.

If a background image is used, specify a default color.

If the connection is slow the background image may not load so specify a color that the text will be legible on.

Provide descriptive alt tags for linking and header images.

For 2 reasons: 1)To accommodate accessibility software for visually handicapped users, and 2)in case a slow connection prevents images from loading.

If a graphic menu is used, provide text alternative.

For same reasons as above. Standard is to use text navigation in the page footer.

Uniform navigation and style throughout the site.

Uniformity creates a sense of comfort for the user and enhances their sense that the company is reliable and dependable.

Link to home on every page (usually via logo).

Clearly distinguish navigation from content.

Indicate current location within the site, via page header and/or navigation.

Provide external links only on substructure pages.

Don't lose visitors to another site before the message is delivered.

For very large images, sound files, etc. provide an option to view/hear. (Don't force a download).

Ensure text is legible against backgrounds.