<Disclaimer>This is personal notes of what I retained during the session. This can be incomplete, partially right or wrong. It is just  part of the notes I took and what retained my attention. Nothing prevents the user to get more information on their favorite web site.</Disclaimer>

Search Server 2008 is a new brand for SharePoint Server 2007 for Search.
Among other things, it has a simplified install, an enhanced administration interface, new federation capabilities, some performance and stability enhancements and does not have document limits.
Search Server 2008 coms in two version : Search Server 2008, which allows a distributed topology and licensed per server, and Search Server 2008 Express for a single server install only, which is free. In terms of features, there is no difference at all.
Michal Gideoni explains when we need to customize the Search. Basically, every time the user interface needs to be modified, the custmozation can be put inplace, and starts with a demo on how to create a new search tab.
To customize the user interface, most of the modifications can be done through the modification of the XSLT generating the HTML, but it is important to know than the Search Web Parts are sealed so not inheritable.
The search supports two types of queries : based on keywords or using
SQL statements. But both of them are using the same flow.
The Search Query web service is useful for remote applications or is accessible from the Office Research Pane and allows the two methods for queries.
The federation is a way to get the search results from other search engine. It sends the query to them, received the result and transforms it to format the output. The Federation Web Part can only be connected to a simple federated search location defined in MOSS and supports synchronous or asynchronous rendering.
Currently, the Federation Web Part supports two types of locations : OpenSearch 1.0/1.1 that must return XML results or even simpler ATOM or RSS/RDF feeds, and Local Search Index. In case OpenSearch is not available or the result is not in XML, it is possible to implement a custom connector that will wrap the result and generate the XML needed by the web part. To do that, it is needed to :
1.- Create an aspx page that take a parametrized URL
2.- Connect to the federated search engine and generate an RSS feed
3.- In the Federation Web Part, connects to that aspx page.