Put a scrollbar on HOMEPAGE BOXES:

div#mainbox_ (NUMBER depends on the positioning of boxes in the Home Page)

div#mainbox_ (NUMBER depends on the Position of boxes in the Home Page)
number 1 for the first box
number 2 for the second box
etc. etc..

as for an example, the site of babatom, the music box is placed 4th on the HOMEPAGE..
1 - Welcome Box
2 - Photos Box
3 - Videos Box
4 - Music Box

so the code is:

div#mainbox_4 .itembox {
overflow-y: auto;
height:200px;
}

For the Guestbook, there's another Option:

#home_guestbook .replybox {
overflow:auto;
}

Put Scroll on the TAG LIST:

div#mainbox_1 div.relatedlinks {
width:780px;
height: 600px;
overflow-x:auto;
width: 780px;
overflow-y: auto;
}


Other Related Posts:
http://makulitrepublic.multiply.com/journal/item/8
http://makulitrepublic.multiply.com/journal/item/7
http://makulitrepublic.multiply.com/journal/item/46

The recent introduction of Multiply 3.0, in the category of oft-requested features, also introduced the ability to completely hide certain content types from your homepage when using the "Boxes View" site layout. This means that the way your site is presented to those who visit... is entirely in your hands.

Note that the changes you make to your page are, of course, only cosmetic in nature. Hiding a certain type of content does not delete it as well. Content types you've hidden are still accessible by visiting your dedicated pages for photos, videos, and so forth.

And yes, you can restore content types you've hidden! Every time you hide one, you'll see a "Restore" link appear for that type in your homepage's sidebar. The links will, naturally, only appear for you (and not your visitors) when viewing your own page, and will allow you to quickly and painlessly snap that section back where it goes, pronto.


Source: http://multiply.multiply.com/journal/item/119/New_3.0_features_Hide_homepage_boxes

div#mainbox_1 .itembox,
div#mainbox_2 .itembox,
div#mainbox_3 .itembox,
div#mainbox_4 .itembox,
div#mainbox_5 .itembox,
div#mainbox_6 .itembox,
div#mainbox_7 .itembox,
div#mainbox_8 .itembox,
div#mainbox_9 .itembox,
div#mainbox_10 .itembox,
div#mainbox_11 .itembox {
-moz-opacity:0.70;
filter:alpha(opacity=70);
opacity:0.70;
-khtml-opacity:0.70;
}

div#mainbox_ (NUMBER depends on the positioning of boxes in the Home Page)

example for single boxes:

div#mainbox_1 .itembox {
-moz-opacity:0.70;
filter:alpha(opacity=70);
opacity:0.70;
-khtml-opacity:0.70;
}


You can also add the code in other parts of your CSS like .itembox etc..

sample:

.itembox {
-moz-opacity:0.70;
filter:alpha(opacity=70);
opacity:0.70;
-khtml-opacity:0.70;
}

/* FOR THE ITEM BOX MAIN CONTENT */
div#mainbox_1 .itemboxsub {
background-attachment: fixed;
position: absolute;
top: 200px;
left: 150px;
height: 100px;
width: 100px;
}

/* FOR THE TITLE BOX OF THE ITEM BOX CONTENT */
#mainbox_1 .itembox {
background-attachment: fixed;
position: absolute;
top: 300px;
left: 150px;
height: 50px;
width: 169px;
overflow: auto;
}

or other boxes just change the value i.e. #mainbox_1 and #mainbox_1 from 1 up.