Clean announcement plugin that reveals a neat popup when user visits your site. You can set who sees the announcement and when to display it. You can set a background image and specify the dimension of your pop up window. This can be used for one timed announcements, adverts or reminders.

WP Announce

Clean  announcement plugin  that reveals a neat popup when users visit your site. You can set who sees the announcement and when to display it.

eewee

Opening a popup ad when loading a page. Popup is little systematically load when opening the dough host site, or appear only at the first visit. You can choose to bring up a visual and / or text, and choose the color & width of the border of the popup.
PS: question, <a href="http://www.eewee.fr" rel="nofollow ugc">eewee.fr</a>.
<ul>
<li>See the <a href="https://wordpress.org/extend/plugins/eewee-popup/changelog/" rel="ugc">Changelog</a> for what’s new.</li>
</ul>

eewee popup

Opening a popup ad when loading a page. Popup is little systematically load when opening the dough host site, or appear only at the first visit.

WP Announce vs eewee popup