Josh

This plugin will allow you to add a custom welcome message to your login/register screens. It will also allow you to add a separate custom message for your logout screen. The admin page allows you to add HTML code into the message boxes, so you can include images, links, videos, or any other HTML code. The options are only limited by your imagination. Check out the screenshots for an example.
Features:
<ul>
<li>Add a custom welcome message to all users who visit your login/register page.</li>
<li>Add a separate custom message to your logout page.</li>
<li>Change the default wordpress logo to your own custom image.</li>
<li>Change the default hover text from “Powered by WordPress” to your own custom message.</li>
<li>Change the default logo link from “www.wordpress.org” to your own custom link.</li>
<li>Manipulate the CSS for the message boxes to make beautiful effects and custom styles.</li>
<li>Add links, images, videos, embeds, iframes, or any other HTML compliant tags.</li>
</ul>
Support: 
<a href="http://forum.joshlobe.com/member.php?action=register&referrer=1" rel="nofollow ugc">Visit my support forum.</a> 
<a href="http://www.joshlobe.com/2012/01/wordpress-custom-welcome-messages/" rel="nofollow ugc">Visit my personal blog page for this plugin.</a>
Other Plugins by Me: 
<a href="https://wordpress.org/extend/plugins/ultimate-tinymce/" rel="ugc">Ultimate TinyMCE</a> – Finally unlock the true power of your visual editor.
<h3>Features</h3>
<ul>
<li>Add a custom welcome message to all users who visit your login/register page.</li>
<li>Add a separate custom message to your logout page.</li>
<li>Change the default wordpress logo to your own custom image.</li>
<li>Change the default hover text from “Powered by WordPress” to your own custom message.</li>
<li>Change the default logo link from “www.wordpress.org” to your own custom link.</li>
<li>Manipulate the CSS for the message boxes to make beautiful effects and custom styles.</li>
<li>Add links, images, videos, embeds, iframes, or any other HTML compliant tags.</li>
</ul>

Custom Welcome Messages

This plugin will allow you to add a custom welcome message to your login/register screens.  It will also allow you to add a separate custom message fo …

Keral Patel

Custom Messages In RSS Feed lets you append or prepend any text or HTML to every item in your blog’s RSS feed.
It is handy when your content is syndicated without proper credit: add a copyright notice, a “the post first appeared on…” source link, or a small logo or icon that links back to your site so the attribution travels with your content.
Everything is configured from a single settings page at Settings → Message In RSS Feed.
Features
<ul>
<li>Add a custom message to the start or the end of each feed item.</li>
<li>Plain text or HTML — insert links, images, or a blog logo.</li>
<li>HTML is sanitized automatically, so unsafe tags and scripts can never reach your feed.</li>
<li>Lightweight: no database tables, no front-end assets, just two small options.</li>
</ul>
<h3>Usage</h3>
Open Settings → Message In RSS Feed, type the text or HTML you want to add, choose whether it appears at the start or the end of each feed item, and save. The message is then added to every item in your RSS feed.

Custom Messages In RSS Feed

Insert a custom text or HTML message at the start or end of every item in your RSS feed.

Custom Welcome Messages vs Custom Messages In RSS Feed